Two pipes A and B can fill a tank in 20 and 30 minutes respectively. If both the pipes are used together, then how long will it take to fill the tank?

Related Mcqs:

Two pipes P and Q can fill a cistern in 12 and 15 minutes respectively. Both are opened together, but at the end of 3 minutes the first is turned off. How much longer will the cistern take to fill?

A. 9 1/4 min B. 11 1/4 min C. 7 1/4 min D. 8 1/2 min...

A cistern which could be filled in 9 hours takes one hour more to be filled owing to a leak in its bottom. If the cistern is full in what time will the leak empty it?

A. 45 hrs B. 60 hrs C. 75 hrs D. 90 hrs...

Pipe A can fill a tank in 5 hours, pipe B in 10 hours and pipe C in 30 hours. If all the pipes are open, in how many hours will the tank be filled?

A. 2 B. 2.5 C. 3 D. 3.5...

Pipes A and B can fill a tank in 5 and 6 hours respectively. Pipe C can empty it in 12 hours. If all the three pipes are opened together, then the tank will be filled in?

A. 1 13/17 hours B. 2 8/11 hours C. 3 9/17 hours D. 4 1/2 hours...

Three taps A, B and C can fill a tank in 12, 15 and 20 hours respectively. If A is open all the time and B and C are open for one hour each alternately, the tank will be full is_______?

A. 6 hrs B. 6 2/3 hrs C. 7 hrs D. 7 1/2 hrs...